Variation characteristics of EC and OC in different air quality grades in Nantong were analyzed by using continuous monitoring data from EC/OC online analyzer and automatic air monitoring station(March 2016 to February 2017). Results showed that the hourly mean concentration of EC and OC are 1.25~6.55 and 4.16~24.90 μg/m3 respectively. There is a positive relationship between hourly concentration of EC and OC and the level of air quality(r=0.999，0.963，p＜0.01). ρ（EC）/ρ（PM2.5）and ρ（OC）/ρ（PM2.5） are 3.54%~6.64% and 11.53%~22.18% respectively, which decrease with the risen of the level of air quality in general. There is an obvious SOC pollution in Nantong. Its concentration is 2.29~14.18 μg/m3, which is positive correlated with the air quality level(r=0.921,p＜0.05). ρ（SOC）/ρ（PM2.5）is 5.44%~12.22%, which decreases with the risen of the level of air quality generally. During fine to mild air quality level, the daily change curve of the hourly concentration of EC shows bimodal type, and the daily change curve of the hourly concentration of OC shows unimodal type. While during middle level pollution and heavy pollution, there isn't an obvious daily change rule of daily change curve of the hourly concentration of EC and OC. Except EC in mild air quality level, the concentration of EC and OC are highest in summer in different air quality grades. There isnt an obvious regularity distribution in other seasons. The seasonal changes of EC and OC average concentration of all air quality grades follow the trend,Summer >Winter>Spring>Fall.